Help me stereophonically multitask!

February 18, 2010 1:34 PM

[MacFilter] Anyone know of a piece of OS X software that will allow me to independently set the audio balance (L-R) of different applications?

Basically, I have a task wherein I listen to audio files of intermittent speech (single-word responses every few seconds) and annotate what the person is saying, and also precisely mark onset of each word. That's fine, but it's cripplingly boring, so I listen to podcasts at the same time. I can't do anything else purely visual, like read books/articles, so if I want a simultaneous activity, it has to at least have some audio component.

The problem is that my podcast or TV show obscures the speech that I'm annotating, a problem that can't be fixed by varying the volume levels. I'd like to try assigning my annotation audio to my left earphone, and iTunes to the right. I can't figure out a way to make OS X do this.

(We use a custom piece of software for annotation, so it would be reasonable to ask our Java dev to build it in. Even then, though, it doesn't look like there's a way to set balance just in iTunes.)

I've seen third-party volume controls for separate applications in the past, though I can't think of the name of one at the moment. Are there any that allow you to change L-R balance as well?

Prefer freeware (who doesn't), but nominal price is fine too.

posted by supercres to computers & internet (7 answers total)

Alternatively, has anyone tried to do this and have it crash-and-burn from a human-interface-sensory-overload standpoint? I can handle both audio streams when they're both "centered", but I feel like separating them spatially would help me discern the words in my annotation. (I occasionally have to repeat segments to tell what the word is.)
posted by supercres at 1:39 PM on February 18, 2010

A simple Radio shack component with left right inputs for a dollar or two would work.
Plug an iPod or other device into the left plug and plug your computer into the right.
It doesnt all do it inside os/x but its a quick way to achieve what your doing.
posted by digividal at 1:56 PM on February 18, 2010 [1 favorite]

So you would plug in your headphone into Radio shack split cable.
Then computer into one side, and iPod into the other one.

Alternatively you could try to buy a second usb audio output for the computer, and
direct one application to use the new output, and again combine the output with
a y cable. (I know Skype allows the user to select which audio output to use. I am not sure if iTunes does.)
posted by digividal at 1:58 PM on February 18, 2010

You could use Audio Hijack Pro to capture (in real-time) audio signal from different applications.

Audio Hijack Pro contains a mixer grid. Let's say you hijack Application A (iTunes) and Application B (something else). You can then set up a signal chain like follows:

AppA --> Balance --> output
AppB --> Balance --> output

The Balance component is a 4FX audio unit effect plug-in that is part of the Audio Hijack Pro installation. You would set AppA to, say, the left channel, and AppB to the right channel.

The output will feed to your audio adapter (sound card, built-in or external) for you to listen to.

It's not free, but I think there's a demo for you to test out with your setup. The way it lets you layout channels and effects is incredibly flexible. I use it for making feedback music and it's worth every penny, IMO.
posted by Blazecock Pileon at 2:09 PM on February 18, 2010 [3 favorites]

Ah, I've used Audio Hijack before and everything; I didn't think of that-- hijacking and outputting in real-time. Thanks, BP.
posted by supercres at 2:33 PM on February 18, 2010

You could download Neutrino to play your podcasts and then play through Quicktime the transciption stuff. Both have balance on their outputs and you could set one to left and one to right.
posted by fantasticninety at 2:47 PM on February 18, 2010

Unfortunately, the transcription/annotation is through a custom program (displays annotation marks, waveform, etc.), so that wouldn't work. (Incidentally, our dev just put it on Sourceforge today.)

Got Audio Hijack running, and it does everything perfectly, even without a license (since I'm not recording, I can just stop and start hijacking).

Thanks again, everyone.
posted by supercres at 2:54 PM on February 18, 2010 [1 favorite]